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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Prefix/12
Addresses2^116
/64 networks2^52
Network
2ca0::/12
First address
2ca0::
Last address
2caf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
83,076,749,736,557,242,056,487,941,267,521,536 (2^116)
/64 networks (LANs)
4,503,599,627,370,496 (2^52)
Full form
2ca0:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
a.c.2.ip6.arpa
Split into smaller subnets/28
/13 (2)/14 (4)/15 (8)/16 (16)/20 (256)/24 (4,096)/28 (65,536)

2ca0::/12 makes 65,536 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
12ca0::/282ca0:f:ffff:ffff:ffff:ffff:ffff:ffff
22ca0:10::/282ca0:1f:ffff:ffff:ffff:ffff:ffff:ffff
32ca0:20::/282ca0:2f:ffff:ffff:ffff:ffff:ffff:ffff
42ca0:30::/282ca0:3f:ffff:ffff:ffff:ffff:ffff:ffff
52ca0:40::/282ca0:4f:ffff:ffff:ffff:ffff:ffff:ffff
62ca0:50::/282ca0:5f:ffff:ffff:ffff:ffff:ffff:ffff
72ca0:60::/282ca0:6f:ffff:ffff:ffff:ffff:ffff:ffff
82ca0:70::/282ca0:7f:ffff:ffff:ffff:ffff:ffff:ffff
92ca0:80::/282ca0:8f:ffff:ffff:ffff:ffff:ffff:ffff
102ca0:90::/282ca0:9f:ffff:ffff:ffff:ffff:ffff:ffff
112ca0:a0::/282ca0:af:ffff:ffff:ffff:ffff:ffff:ffff
122ca0:b0::/282ca0:bf:ffff:ffff:ffff:ffff:ffff:ffff
132ca0:c0::/282ca0:cf:ffff:ffff:ffff:ffff:ffff:ffff
142ca0:d0::/282ca0:df:ffff:ffff:ffff:ffff:ffff:ffff
152ca0:e0::/282ca0:ef:ffff:ffff:ffff:ffff:ffff:ffff
162ca0:f0::/282ca0:ff:ffff:ffff:ffff:ffff:ffff:ffff
172ca0:100::/282ca0:10f:ffff:ffff:ffff:ffff:ffff:ffff
182ca0:110::/282ca0:11f:ffff:ffff:ffff:ffff:ffff:ffff
192ca0:120::/282ca0:12f:ffff:ffff:ffff:ffff:ffff:ffff
202ca0:130::/282ca0:13f:ffff:ffff:ffff:ffff:ffff:ffff
212ca0:140::/282ca0:14f:ffff:ffff:ffff:ffff:ffff:ffff
222ca0:150::/282ca0:15f:ffff:ffff:ffff:ffff:ffff:ffff
232ca0:160::/282ca0:16f:ffff:ffff:ffff:ffff:ffff:ffff
242ca0:170::/282ca0:17f:ffff:ffff:ffff:ffff:ffff:ffff
252ca0:180::/282ca0:18f:ffff:ffff:ffff:ffff:ffff:ffff
262ca0:190::/282ca0:19f:ffff:ffff:ffff:ffff:ffff:ffff
272ca0:1a0::/282ca0:1af:ffff:ffff:ffff:ffff:ffff:ffff
282ca0:1b0::/282ca0:1bf:ffff:ffff:ffff:ffff:ffff:ffff
292ca0:1c0::/282ca0:1cf:ffff:ffff:ffff:ffff:ffff:ffff
302ca0:1d0::/282ca0:1df:ffff:ffff:ffff:ffff:ffff:ffff
312ca0:1e0::/282ca0:1ef:ffff:ffff:ffff:ffff:ffff:ffff
322ca0:1f0::/282ca0:1ff:ffff:ffff:ffff:ffff:ffff:ffff
332ca0:200::/282ca0:20f:ffff:ffff:ffff:ffff:ffff:ffff
342ca0:210::/282ca0:21f:ffff:ffff:ffff:ffff:ffff:ffff
352ca0:220::/282ca0:22f:ffff:ffff:ffff:ffff:ffff:ffff
362ca0:230::/282ca0:23f:ffff:ffff:ffff:ffff:ffff:ffff
372ca0:240::/282ca0:24f:ffff:ffff:ffff:ffff:ffff:ffff
382ca0:250::/282ca0:25f:ffff:ffff:ffff:ffff:ffff:ffff
392ca0:260::/282ca0:26f:ffff:ffff:ffff:ffff:ffff:ffff
402ca0:270::/282ca0:27f:ffff:ffff:ffff:ffff:ffff:ffff
412ca0:280::/282ca0:28f:ffff:ffff:ffff:ffff:ffff:ffff
422ca0:290::/282ca0:29f:ffff:ffff:ffff:ffff:ffff:ffff
432ca0:2a0::/282ca0:2af:ffff:ffff:ffff:ffff:ffff:ffff
442ca0:2b0::/282ca0:2bf:ffff:ffff:ffff:ffff:ffff:ffff
452ca0:2c0::/282ca0:2cf:ffff:ffff:ffff:ffff:ffff:ffff
462ca0:2d0::/282ca0:2df:ffff:ffff:ffff:ffff:ffff:ffff
472ca0:2e0::/282ca0:2ef:ffff:ffff:ffff:ffff:ffff:ffff
482ca0:2f0::/282ca0:2ff:ffff:ffff:ffff:ffff:ffff:ffff
492ca0:300::/282ca0:30f:ffff:ffff:ffff:ffff:ffff:ffff
502ca0:310::/282ca0:31f:ffff:ffff:ffff:ffff:ffff:ffff
512ca0:320::/282ca0:32f:ffff:ffff:ffff:ffff:ffff:ffff
522ca0:330::/282ca0:33f:ffff:ffff:ffff:ffff:ffff:ffff
532ca0:340::/282ca0:34f:ffff:ffff:ffff:ffff:ffff:ffff
542ca0:350::/282ca0:35f:ffff:ffff:ffff:ffff:ffff:ffff
552ca0:360::/282ca0:36f:ffff:ffff:ffff:ffff:ffff:ffff
562ca0:370::/282ca0:37f:ffff:ffff:ffff:ffff:ffff:ffff
572ca0:380::/282ca0:38f:ffff:ffff:ffff:ffff:ffff:ffff
582ca0:390::/282ca0:39f:ffff:ffff:ffff:ffff:ffff:ffff
592ca0:3a0::/282ca0:3af:ffff:ffff:ffff:ffff:ffff:ffff
602ca0:3b0::/282ca0:3bf:ffff:ffff:ffff:ffff:ffff:ffff
612ca0:3c0::/282ca0:3cf:ffff:ffff:ffff:ffff:ffff:ffff
622ca0:3d0::/282ca0:3df:ffff:ffff:ffff:ffff:ffff:ffff
632ca0:3e0::/282ca0:3ef:ffff:ffff:ffff:ffff:ffff:ffff
642ca0:3f0::/282ca0:3ff:ffff:ffff:ffff:ffff:ffff:ffff
652ca0:400::/282ca0:40f:ffff:ffff:ffff:ffff:ffff:ffff
662ca0:410::/282ca0:41f:ffff:ffff:ffff:ffff:ffff:ffff
672ca0:420::/282ca0:42f:ffff:ffff:ffff:ffff:ffff:ffff
682ca0:430::/282ca0:43f:ffff:ffff:ffff:ffff:ffff:ffff
692ca0:440::/282ca0:44f:ffff:ffff:ffff:ffff:ffff:ffff
702ca0:450::/282ca0:45f:ffff:ffff:ffff:ffff:ffff:ffff
712ca0:460::/282ca0:46f:ffff:ffff:ffff:ffff:ffff:ffff
722ca0:470::/282ca0:47f:ffff:ffff:ffff:ffff:ffff:ffff
732ca0:480::/282ca0:48f:ffff:ffff:ffff:ffff:ffff:ffff
742ca0:490::/282ca0:49f:ffff:ffff:ffff:ffff:ffff:ffff
752ca0:4a0::/282ca0:4af:ffff:ffff:ffff:ffff:ffff:ffff
762ca0:4b0::/282ca0:4bf:ffff:ffff:ffff:ffff:ffff:ffff
772ca0:4c0::/282ca0:4cf:ffff:ffff:ffff:ffff:ffff:ffff
782ca0:4d0::/282ca0:4df:ffff:ffff:ffff:ffff:ffff:ffff
792ca0:4e0::/282ca0:4ef:ffff:ffff:ffff:ffff:ffff:ffff
802ca0:4f0::/282ca0:4ff:ffff:ffff:ffff:ffff:ffff:ffff
812ca0:500::/282ca0:50f:ffff:ffff:ffff:ffff:ffff:ffff
822ca0:510::/282ca0:51f:ffff:ffff:ffff:ffff:ffff:ffff
832ca0:520::/282ca0:52f:ffff:ffff:ffff:ffff:ffff:ffff
842ca0:530::/282ca0:53f:ffff:ffff:ffff:ffff:ffff:ffff
852ca0:540::/282ca0:54f:ffff:ffff:ffff:ffff:ffff:ffff
862ca0:550::/282ca0:55f:ffff:ffff:ffff:ffff:ffff:ffff
872ca0:560::/282ca0:56f:ffff:ffff:ffff:ffff:ffff:ffff
882ca0:570::/282ca0:57f:ffff:ffff:ffff:ffff:ffff:ffff
892ca0:580::/282ca0:58f:ffff:ffff:ffff:ffff:ffff:ffff
902ca0:590::/282ca0:59f:ffff:ffff:ffff:ffff:ffff:ffff
912ca0:5a0::/282ca0:5af:ffff:ffff:ffff:ffff:ffff:ffff
922ca0:5b0::/282ca0:5bf:ffff:ffff:ffff:ffff:ffff:ffff
932ca0:5c0::/282ca0:5cf:ffff:ffff:ffff:ffff:ffff:ffff
942ca0:5d0::/282ca0:5df:ffff:ffff:ffff:ffff:ffff:ffff
952ca0:5e0::/282ca0:5ef:ffff:ffff:ffff:ffff:ffff:ffff
962ca0:5f0::/282ca0:5ff:ffff:ffff:ffff:ffff:ffff:ffff
972ca0:600::/282ca0:60f:ffff:ffff:ffff:ffff:ffff:ffff
982ca0:610::/282ca0:61f:ffff:ffff:ffff:ffff:ffff:ffff
992ca0:620::/282ca0:62f:ffff:ffff:ffff:ffff:ffff:ffff
1002ca0:630::/282ca0:63f:ffff:ffff:ffff:ffff:ffff:ffff
1012ca0:640::/282ca0:64f:ffff:ffff:ffff:ffff:ffff:ffff
1022ca0:650::/282ca0:65f:ffff:ffff:ffff:ffff:ffff:ffff
1032ca0:660::/282ca0:66f:ffff:ffff:ffff:ffff:ffff:ffff
1042ca0:670::/282ca0:67f:ffff:ffff:ffff:ffff:ffff:ffff
1052ca0:680::/282ca0:68f:ffff:ffff:ffff:ffff:ffff:ffff
1062ca0:690::/282ca0:69f:ffff:ffff:ffff:ffff:ffff:ffff
1072ca0:6a0::/282ca0:6af:ffff:ffff:ffff:ffff:ffff:ffff
1082ca0:6b0::/282ca0:6bf:ffff:ffff:ffff:ffff:ffff:ffff
1092ca0:6c0::/282ca0:6cf:ffff:ffff:ffff:ffff:ffff:ffff
1102ca0:6d0::/282ca0:6df:ffff:ffff:ffff:ffff:ffff:ffff
1112ca0:6e0::/282ca0:6ef:ffff:ffff:ffff:ffff:ffff:ffff
1122ca0:6f0::/282ca0:6ff:ffff:ffff:ffff:ffff:ffff:ffff
1132ca0:700::/282ca0:70f:ffff:ffff:ffff:ffff:ffff:ffff
1142ca0:710::/282ca0:71f:ffff:ffff:ffff:ffff:ffff:ffff
1152ca0:720::/282ca0:72f:ffff:ffff:ffff:ffff:ffff:ffff
1162ca0:730::/282ca0:73f:ffff:ffff:ffff:ffff:ffff:ffff
1172ca0:740::/282ca0:74f:ffff:ffff:ffff:ffff:ffff:ffff
1182ca0:750::/282ca0:75f:ffff:ffff:ffff:ffff:ffff:ffff
1192ca0:760::/282ca0:76f:ffff:ffff:ffff:ffff:ffff:ffff
1202ca0:770::/282ca0:77f:ffff:ffff:ffff:ffff:ffff:ffff
1212ca0:780::/282ca0:78f:ffff:ffff:ffff:ffff:ffff:ffff
1222ca0:790::/282ca0:79f:ffff:ffff:ffff:ffff:ffff:ffff
1232ca0:7a0::/282ca0:7af:ffff:ffff:ffff:ffff:ffff:ffff
1242ca0:7b0::/282ca0:7bf:ffff:ffff:ffff:ffff:ffff:ffff
1252ca0:7c0::/282ca0:7cf:ffff:ffff:ffff:ffff:ffff:ffff
1262ca0:7d0::/282ca0:7df:ffff:ffff:ffff:ffff:ffff:ffff
1272ca0:7e0::/282ca0:7ef:ffff:ffff:ffff:ffff:ffff:ffff
1282ca0:7f0::/282ca0:7ff:ffff:ffff:ffff:ffff:ffff:ffff
1292ca0:800::/282ca0:80f:ffff:ffff:ffff:ffff:ffff:ffff
1302ca0:810::/282ca0:81f:ffff:ffff:ffff:ffff:ffff:ffff
1312ca0:820::/282ca0:82f:ffff:ffff:ffff:ffff:ffff:ffff
1322ca0:830::/282ca0:83f:ffff:ffff:ffff:ffff:ffff:ffff
1332ca0:840::/282ca0:84f:ffff:ffff:ffff:ffff:ffff:ffff
1342ca0:850::/282ca0:85f:ffff:ffff:ffff:ffff:ffff:ffff
1352ca0:860::/282ca0:86f:ffff:ffff:ffff:ffff:ffff:ffff
1362ca0:870::/282ca0:87f:ffff:ffff:ffff:ffff:ffff:ffff
1372ca0:880::/282ca0:88f:ffff:ffff:ffff:ffff:ffff:ffff
1382ca0:890::/282ca0:89f:ffff:ffff:ffff:ffff:ffff:ffff
1392ca0:8a0::/282ca0:8af:ffff:ffff:ffff:ffff:ffff:ffff
1402ca0:8b0::/282ca0:8bf:ffff:ffff:ffff:ffff:ffff:ffff
1412ca0:8c0::/282ca0:8cf:ffff:ffff:ffff:ffff:ffff:ffff
1422ca0:8d0::/282ca0:8df:ffff:ffff:ffff:ffff:ffff:ffff
1432ca0:8e0::/282ca0:8ef:ffff:ffff:ffff:ffff:ffff:ffff
1442ca0:8f0::/282ca0:8ff:ffff:ffff:ffff:ffff:ffff:ffff
1452ca0:900::/282ca0:90f:ffff:ffff:ffff:ffff:ffff:ffff
1462ca0:910::/282ca0:91f:ffff:ffff:ffff:ffff:ffff:ffff
1472ca0:920::/282ca0:92f:ffff:ffff:ffff:ffff:ffff:ffff
1482ca0:930::/282ca0:93f:ffff:ffff:ffff:ffff:ffff:ffff
1492ca0:940::/282ca0:94f:ffff:ffff:ffff:ffff:ffff:ffff
1502ca0:950::/282ca0:95f:ffff:ffff:ffff:ffff:ffff:ffff
1512ca0:960::/282ca0:96f:ffff:ffff:ffff:ffff:ffff:ffff
1522ca0:970::/282ca0:97f:ffff:ffff:ffff:ffff:ffff:ffff
1532ca0:980::/282ca0:98f:ffff:ffff:ffff:ffff:ffff:ffff
1542ca0:990::/282ca0:99f:ffff:ffff:ffff:ffff:ffff:ffff
1552ca0:9a0::/282ca0:9af:ffff:ffff:ffff:ffff:ffff:ffff
1562ca0:9b0::/282ca0:9bf:ffff:ffff:ffff:ffff:ffff:ffff
1572ca0:9c0::/282ca0:9cf:ffff:ffff:ffff:ffff:ffff:ffff
1582ca0:9d0::/282ca0:9df:ffff:ffff:ffff:ffff:ffff:ffff
1592ca0:9e0::/282ca0:9ef:ffff:ffff:ffff:ffff:ffff:ffff
1602ca0:9f0::/282ca0:9ff:ffff:ffff:ffff:ffff:ffff:ffff
1612ca0:a00::/282ca0:a0f:ffff:ffff:ffff:ffff:ffff:ffff
1622ca0:a10::/282ca0:a1f:ffff:ffff:ffff:ffff:ffff:ffff
1632ca0:a20::/282ca0:a2f:ffff:ffff:ffff:ffff:ffff:ffff
1642ca0:a30::/282ca0:a3f:ffff:ffff:ffff:ffff:ffff:ffff
1652ca0:a40::/282ca0:a4f:ffff:ffff:ffff:ffff:ffff:ffff
1662ca0:a50::/282ca0:a5f:ffff:ffff:ffff:ffff:ffff:ffff
1672ca0:a60::/282ca0:a6f:ffff:ffff:ffff:ffff:ffff:ffff
1682ca0:a70::/282ca0:a7f:ffff:ffff:ffff:ffff:ffff:ffff
1692ca0:a80::/282ca0:a8f:ffff:ffff:ffff:ffff:ffff:ffff
1702ca0:a90::/282ca0:a9f:ffff:ffff:ffff:ffff:ffff:ffff
1712ca0:aa0::/282ca0:aaf:ffff:ffff:ffff:ffff:ffff:ffff
1722ca0:ab0::/282ca0:abf:ffff:ffff:ffff:ffff:ffff:ffff
1732ca0:ac0::/282ca0:acf:ffff:ffff:ffff:ffff:ffff:ffff
1742ca0:ad0::/282ca0:adf:ffff:ffff:ffff:ffff:ffff:ffff
1752ca0:ae0::/282ca0:aef:ffff:ffff:ffff:ffff:ffff:ffff
1762ca0:af0::/282ca0:aff:ffff:ffff:ffff:ffff:ffff:ffff
1772ca0:b00::/282ca0:b0f:ffff:ffff:ffff:ffff:ffff:ffff
1782ca0:b10::/282ca0:b1f:ffff:ffff:ffff:ffff:ffff:ffff
1792ca0:b20::/282ca0:b2f:ffff:ffff:ffff:ffff:ffff:ffff
1802ca0:b30::/282ca0:b3f:ffff:ffff:ffff:ffff:ffff:ffff
1812ca0:b40::/282ca0:b4f:ffff:ffff:ffff:ffff:ffff:ffff
1822ca0:b50::/282ca0:b5f:ffff:ffff:ffff:ffff:ffff:ffff
1832ca0:b60::/282ca0:b6f:ffff:ffff:ffff:ffff:ffff:ffff
1842ca0:b70::/282ca0:b7f:ffff:ffff:ffff:ffff:ffff:ffff
1852ca0:b80::/282ca0:b8f:ffff:ffff:ffff:ffff:ffff:ffff
1862ca0:b90::/282ca0:b9f:ffff:ffff:ffff:ffff:ffff:ffff
1872ca0:ba0::/282ca0:baf:ffff:ffff:ffff:ffff:ffff:ffff
1882ca0:bb0::/282ca0:bbf:ffff:ffff:ffff:ffff:ffff:ffff
1892ca0:bc0::/282ca0:bcf:ffff:ffff:ffff:ffff:ffff:ffff
1902ca0:bd0::/282ca0:bdf:ffff:ffff:ffff:ffff:ffff:ffff
1912ca0:be0::/282ca0:bef:ffff:ffff:ffff:ffff:ffff:ffff
1922ca0:bf0::/282ca0:bff:ffff:ffff:ffff:ffff:ffff:ffff
1932ca0:c00::/282ca0:c0f:ffff:ffff:ffff:ffff:ffff:ffff
1942ca0:c10::/282ca0:c1f:ffff:ffff:ffff:ffff:ffff:ffff
1952ca0:c20::/282ca0:c2f:ffff:ffff:ffff:ffff:ffff:ffff
1962ca0:c30::/282ca0:c3f:ffff:ffff:ffff:ffff:ffff:ffff
1972ca0:c40::/282ca0:c4f:ffff:ffff:ffff:ffff:ffff:ffff
1982ca0:c50::/282ca0:c5f:ffff:ffff:ffff:ffff:ffff:ffff
1992ca0:c60::/282ca0:c6f:ffff:ffff:ffff:ffff:ffff:ffff
2002ca0:c70::/282ca0:c7f:ffff:ffff:ffff:ffff:ffff:ffff
2012ca0:c80::/282ca0:c8f:ffff:ffff:ffff:ffff:ffff:ffff
2022ca0:c90::/282ca0:c9f:ffff:ffff:ffff:ffff:ffff:ffff
2032ca0:ca0::/282ca0:caf:ffff:ffff:ffff:ffff:ffff:ffff
2042ca0:cb0::/282ca0:cbf:ffff:ffff:ffff:ffff:ffff:ffff
2052ca0:cc0::/282ca0:ccf:ffff:ffff:ffff:ffff:ffff:ffff
2062ca0:cd0::/282ca0:cdf:ffff:ffff:ffff:ffff:ffff:ffff
2072ca0:ce0::/282ca0:cef:ffff:ffff:ffff:ffff:ffff:ffff
2082ca0:cf0::/282ca0:cff:ffff:ffff:ffff:ffff:ffff:ffff
2092ca0:d00::/282ca0:d0f:ffff:ffff:ffff:ffff:ffff:ffff
2102ca0:d10::/282ca0:d1f:ffff:ffff:ffff:ffff:ffff:ffff
2112ca0:d20::/282ca0:d2f:ffff:ffff:ffff:ffff:ffff:ffff
2122ca0:d30::/282ca0:d3f:ffff:ffff:ffff:ffff:ffff:ffff
2132ca0:d40::/282ca0:d4f:ffff:ffff:ffff:ffff:ffff:ffff
2142ca0:d50::/282ca0:d5f:ffff:ffff:ffff:ffff:ffff:ffff
2152ca0:d60::/282ca0:d6f:ffff:ffff:ffff:ffff:ffff:ffff
2162ca0:d70::/282ca0:d7f:ffff:ffff:ffff:ffff:ffff:ffff
2172ca0:d80::/282ca0:d8f:ffff:ffff:ffff:ffff:ffff:ffff
2182ca0:d90::/282ca0:d9f:ffff:ffff:ffff:ffff:ffff:ffff
2192ca0:da0::/282ca0:daf:ffff:ffff:ffff:ffff:ffff:ffff
2202ca0:db0::/282ca0:dbf:ffff:ffff:ffff:ffff:ffff:ffff
2212ca0:dc0::/282ca0:dcf:ffff:ffff:ffff:ffff:ffff:ffff
2222ca0:dd0::/282ca0:ddf:ffff:ffff:ffff:ffff:ffff:ffff
2232ca0:de0::/282ca0:def:ffff:ffff:ffff:ffff:ffff:ffff
2242ca0:df0::/282ca0:dff:ffff:ffff:ffff:ffff:ffff:ffff
2252ca0:e00::/282ca0:e0f:ffff:ffff:ffff:ffff:ffff:ffff
2262ca0:e10::/282ca0:e1f:ffff:ffff:ffff:ffff:ffff:ffff
2272ca0:e20::/282ca0:e2f:ffff:ffff:ffff:ffff:ffff:ffff
2282ca0:e30::/282ca0:e3f:ffff:ffff:ffff:ffff:ffff:ffff
2292ca0:e40::/282ca0:e4f:ffff:ffff:ffff:ffff:ffff:ffff
2302ca0:e50::/282ca0:e5f:ffff:ffff:ffff:ffff:ffff:ffff
2312ca0:e60::/282ca0:e6f:ffff:ffff:ffff:ffff:ffff:ffff
2322ca0:e70::/282ca0:e7f:ffff:ffff:ffff:ffff:ffff:ffff
2332ca0:e80::/282ca0:e8f:ffff:ffff:ffff:ffff:ffff:ffff
2342ca0:e90::/282ca0:e9f:ffff:ffff:ffff:ffff:ffff:ffff
2352ca0:ea0::/282ca0:eaf:ffff:ffff:ffff:ffff:ffff:ffff
2362ca0:eb0::/282ca0:ebf:ffff:ffff:ffff:ffff:ffff:ffff
2372ca0:ec0::/282ca0:ecf:ffff:ffff:ffff:ffff:ffff:ffff
2382ca0:ed0::/282ca0:edf:ffff:ffff:ffff:ffff:ffff:ffff
2392ca0:ee0::/282ca0:eef:ffff:ffff:ffff:ffff:ffff:ffff
2402ca0:ef0::/282ca0:eff:ffff:ffff:ffff:ffff:ffff:ffff
2412ca0:f00::/282ca0:f0f:ffff:ffff:ffff:ffff:ffff:ffff
2422ca0:f10::/282ca0:f1f:ffff:ffff:ffff:ffff:ffff:ffff
2432ca0:f20::/282ca0:f2f:ffff:ffff:ffff:ffff:ffff:ffff
2442ca0:f30::/282ca0:f3f:ffff:ffff:ffff:ffff:ffff:ffff
2452ca0:f40::/282ca0:f4f:ffff:ffff:ffff:ffff:ffff:ffff
2462ca0:f50::/282ca0:f5f:ffff:ffff:ffff:ffff:ffff:ffff
2472ca0:f60::/282ca0:f6f:ffff:ffff:ffff:ffff:ffff:ffff
2482ca0:f70::/282ca0:f7f:ffff:ffff:ffff:ffff:ffff:ffff
2492ca0:f80::/282ca0:f8f:ffff:ffff:ffff:ffff:ffff:ffff
2502ca0:f90::/282ca0:f9f:ffff:ffff:ffff:ffff:ffff:ffff
2512ca0:fa0::/282ca0:faf:ffff:ffff:ffff:ffff:ffff:ffff
2522ca0:fb0::/282ca0:fbf:ffff:ffff:ffff:ffff:ffff:ffff
2532ca0:fc0::/282ca0:fcf:ffff:ffff:ffff:ffff:ffff:ffff
2542ca0:fd0::/282ca0:fdf:ffff:ffff:ffff:ffff:ffff:ffff
2552ca0:fe0::/282ca0:fef:ffff:ffff:ffff:ffff:ffff:ffff
2562ca0:ff0::/282ca0:fff:ffff:ffff:ffff:ffff:ffff:ffff

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.